def hw(s):
    l = len(s)
    for i in range(l // 2):
        if s[i] != s[l - 1 - i]:
            return 0
    return 1
def main():
    s = input("输入字符串：")
    c = hw(s)
    if c==0:
        print("该字符串不是回文")
    elif c==1:
        print("该字符串是回文")
if __name__ == '__main__':
    main()